A conventional machining method is to be performed by a machining system including a machine tool and a computer that is connected electrically to the machine tool and that is used to control operation of the machine tool. Referring to FIG. 1, the machine tool includes a table 12 for supporting a plate-shaped workpiece 11, and a tool 13 disposed relative to the table 12. When the workpiece 11 is to be machined, the computer (not shown) first controls the tool 13 to move horizontally to a machining position 14, next controls the tool 13 to move vertically toward the workpiece 11 to a stand-by height 15, and then controls the tool 13 to move vertically toward the workpiece 11 to a machining height 16 to machine the workpiece 11. After that, the computer controls the tool 13 to move vertically back to the stand-by height 15, and later controls the tool 13 to move horizontally to a next machining position 17. When the tool 13 has been moved to arrive at the next machining position 17, the computer controls the tool 13 to move vertically toward the workpiece 11 once again to the machining height 16 to machine the workpiece 11, and finally controls the tool 13 to move vertically away from the workpiece 11 and back to the stand-by height 15. The aforementioned steps are performed repeatedly to implement machining operation.
It is evident from the above that, in the conventional machining method, the tool 13 is moved either horizontally or vertically. However, the aforementioned approach for moving the tool 13 is relatively inefficient, and the overall time required for the machining operation is increased.